Effect of vertical dipole temperature anomalies on convection in a cloud model

Marja Bister, Brian E Mapes

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A cloud-resolving model is used to study the effects of a vertical temperature dipole on convective cloud development. Such dipole anomalies, with a warm-above-cool structure in the troposphere, are known to be forced by mesoscale convective systems (MCSs) in the Tropics. The experiments involve letting convection develop in perturbed initial soundings with open lateral boundary conditions. Convection is driven solely by surface fluxes. In the control run, a field of deep convection ensues. With a strong dipole anomaly that is warm in the upper troposphere, no clouds ascend beyond the middle troposphere. In this case, cumulus congestus clouds strongly moisten the midtroposphere with relative humidity increases by up to 24% by the end of the 6-h simulation. With a half-strength anomaly, a mixed population results: mainly middle-topped congestus clouds, but with some intermittent deep cells. The partitioning between cloud types is somewhat sensitive to model resolution, with a change from 1- to 0.5-km grid spacing resulting in relatively more congestus clouds and fewer deep cells.

Original languageEnglish (US)
Pages (from-to)2092-2100
Number of pages9
JournalJournal of the Atmospheric Sciences
Volume61
Issue number16
DOIs
StatePublished - Aug 15 2004
Externally publishedYes

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temperature anomaly
convection
troposphere
anomaly
convective cloud
convective system
surface flux
cumulus
effect
relative humidity
spacing
boundary condition
partitioning
simulation
experiment
temperature

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Effect of vertical dipole temperature anomalies on convection in a cloud model. / Bister, Marja; Mapes, Brian E.

In: Journal of the Atmospheric Sciences, Vol. 61, No. 16, 15.08.2004, p. 2092-2100.

Research output: Contribution to journalArticle

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